From 9dd05df8403bda5b68178b795c554b3940628bb6 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 3 Feb 2025 13:58:16 -0800 Subject: [PATCH] net: warn if NAPI instance wasn't shut down Drivers should always disable a NAPI instance before removing it. If they don't the instance may be queued for polling. Since commit 86e25f40aa1e ("net: napi: Add napi_config") we also remove the NAPI from the busy polling hash table in napi_disable(), so not disabling would leave a stale entry there. Use of busy polling is relatively uncommon so bugs may be lurking in the drivers. Add an explicit warning. Reviewed-by: Joe Damato Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250203215816.1294081-1-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/core/dev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index c0021cbd28fc1..2b141f20b13b5 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7071,6 +7071,9 @@ void __netif_napi_del_locked(struct napi_struct *napi) if (!test_and_clear_bit(NAPI_STATE_LISTED, &napi->state)) return; + /* Make sure NAPI is disabled (or was never enabled). */ + WARN_ON(!test_bit(NAPI_STATE_SCHED, &napi->state)); + if (napi->config) { napi->index = -1; napi->config = NULL; -- 2.39.5